I use Steam VR for work every day, but when doing my own personal development it became very frustrating to have to constantly close it every time I opened up the launcher.
The previously mentioned trick of editing the file in “C:\Program Files\Epic Games\UE_4.25\Engine\Plugins\Runtime\Steam\SteamVR\SteamVR.uplugin” worked perfectly. Setting enabled by default to false fixed it instantly for me.